Distillation principles

For an ideal mixture of two liquids, the vapor pressures are related to the composition in the liquid mixture by Raoult s law (Frangois-Marie RaouU, see box)  

Pbenzene benzene l sat,benzene od Putluene luene Psat,toluene 

According to Dalton s law (John Dalton, see box), the molar fractions in the vapor phase of a benzene-toluene mixture are related to the partial pressures and the total pressure, p, by  

Thus strictly speaking, the relative volatility is always a function of temperature as the vaporization enthalpies are unlikely to be identical. However, if the values of Avapfr are approximately the same, we can use an average value for a. For example, benzene,toiuene IS 2.61 at 80 °C (boUing point of pure benzene at 1 bar) and 2.32 at 111 °C (boiling point of toluene), so we may use a mean value of 2.46. A stronger variation of a with the composition of the mixture is discussed in Example 3.3.2 for a mixture of methanol and water. 

A useful simple equation for the vapor-liquid equilibrium can be derived as follows. Combination of the laws of Raoult and Dalton, Eqs. (3.3.6) and (3.3.7), yields  

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J. Stichlmair and J.R. Fair, Distillation Principles and Practices, J. Wiley and Sons, New York, 1998. ISBN 0471252417. 

Hengstebeck, R. J., Distillation-Principles and Design Practices, Reinhold Publishing, 1961. 

Hengstebeck, R.J., Jr. Distillation -Principles and Design Practice, Reinhold, New York, 1961. 

R.J. Hengstebeck, Distillation principles and design procedures, Reinhold Publishing Co., New-York (1961). 

Stichlmair and Fair (Distillation Principles and Practice, Wiley -VCH, New York, 1998) show that liquid holdup is primarily a function of the liquid Froude number, specific surface area of the packing, and physical properties. They recommend the correction by Engel, Stichlmair, and Geipel [Ind. Eng. Chem. Symp. Ser. 142, 939 (1997)]. 

Stichlmair JG, Fair JR. Distillation Principles and Practice. New York Wiley-VCH, 1998. 

Hengstebeck, R. J., Stage and Reflux Requirements, Distillation Principles and Design Procedures, Robert E. Krieger, Huntington, NY, 1976, Charts 7 and 8. 

Equation (3.48) is known as point efficiency, having been given in a number of publications, one notable one being Distillation Principles and Design Procedures [7]. Equation (3.48) is the two-film method of predicting the ETF tray one-point efficiency, and refers to a small element of a tray that must be converted to a Murphree efficiency (Eq. 3.47) [8],... 

Stichlmair J.G., Frey J.R., Distillation, Principles and Practice, Wiley-VCH, Weinheim, Germany, 1999... 

Etherifications of various olefins can be conducted on the catalytic distillation principle, using methanol, ethanol, propanol, butanol etc., and the additional advantages of employing OCFS are equally relevant for many of these. 

Stichlmair, J.G. Fair, J.R. Distillation Principles and Practice Wiley-VCH New York, 1998. 

FIGURE 12.14 Ternary diagram of a system containing three binary azeotropes and one ternary azeotrope. Arrows denote direction the distillation will proceed in, based on starting mixtures. (J. Stichlmair, J. R. Fair, 1998. Distillation—Principles and Practices. New York Wiley-VCH.)... 

Elliot, C. Distillation Principles. London, 1925. Hausbrand, E. Principles and Practice of Industrial Distillation. Trans, from the 4th German ed. by E. H. Tripp. London, 1925. 

Young, Sydney. Distillation Principles and Processes. London, 1922. 

Stichlmair, J., J.R. Fair, J. L. Bravo, 1989, Separation of azeotropic mixture via enhanced distillation, Chem. Eng. Progress, 85(1), 63-69 Stichlmair, J., J. R. Herguijuela, 1992, Separation regions and processes of zeotropic and azeotropic ternary distillation, AIChEJ, 38, p. 1523-1535 Stichlmair, J. G., J. R. Fair, 1999, Distillation, Principles and Practice, Willey-VCH Strathmann, H., 1990, Membrane and Membrane Separation Processes, Ullmann s Encyclopaedia of Industrial Chemistry, vol. A16 Taylor, R., Krishna, R., 2000, Modelling reactive distillation, Chem. Eng. Sci., 52, 993-1005... 

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